# the law appoints as high priests men who have weaknesses

"according to the law, men appoint as high priests men who are spiritually weak" or "for according to the law, men who are weak against sin are appointed as high priests"

# the word of the oath, which came after the law, appointed a Son

"God appointed a Son by his oath, which he made after he gave the law, a Son" or "after he had given the law, God swore an oath and appointed his Son". These are important titles that describe the relationship between God and Jesus. It is best to translate “Father” and “Son” with the same words that your language uses to refer to a human father and a human son.

# who has been made perfect

"who has completely obeyed God and become mature"